A347539 - OEIS

%I #14 Sep 30 2021 09:48:35

%S 1,2,3,4,5,7,6,8,11,17,13,10,19,14,9,12,16,31,59,41,29,22,67,43,34,23,

%T 37,26,15,20,53,38,21,28,18,24,32,127,277,179,109,79,62,331,191,139,

%U 118,83,157,101,82,47,71,58,33,44,241,163,134,73,107,86,51,68

%N Matula-Goebel number of the n-th tree in Beyer and Hedetniemi's rooted tree iteration (A346913).

%C This sequence is a permutation of the natural numbers, with inverse A347540.

%H Kevin Ryde, <a href="/A347539/b347539.txt">Table of n, a(n) for n = 1..7813</a> (trees <= 12 vertices)

%H <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>

%e For n=33, row 33 of A346913 is levels sequence 1,2,3,3,2,3 which is the following tree,

%e   root      21          a(33) = 21 Matula-Goebel number

%e             |  \        (being prime(4)*prime(2) = 21)

%e   children  4    2

%e             |\   |

%e             1 1  1

%Y Cf. A346913, A347540 (inverse), A061773, A127301.

%K nonn

%O 1,2

%A _Kevin Ryde_, Sep 06 2021